Fruit + Meat = Good?

This post is about our second attempt at Tacos al Pastor which is essentially pork and pineapple on corn tortillas.  We chose to use this recipe that we found highly rated on Epicurious both times. The first time we cooked it, the flavors were great but we followed the marination schedule to the letter and wound up with very mushy meat.  Very mushy.  We knew that pineapple has an enzyme that can tenderize meat, but 4 hours is just way too long to marinate, even with 1/2 inch thick pork.  Chris and Monica were troopers for eating it at all.

So the second time, we did a bit of research and determined that the enzyme is bromelain and tenderizes meat via a process called "forking".  This enzyme is heat-labile and loses its ability to fork/tenderize meat above 65C, so fresh pineapple does it, but canned and pasteurized pineapple juice does not.  We added the marinade an hour before dinner rather then the four hours the first time we tried it and figured that we were safe.  Wrong again!  The combination of too-thinly-cut meat and the full hour produced mushy meat, albeit less mushy than the first attempt.

But the flavors keep calling us back.  The next time, we will take the advice of this blogger who recommends holding the crushed pineapple and juice back until 30 minutes until the meat hits the grill.

Additionally, the first time we made this dish, we didn't have a tortilla press so that process took forever.  Our guests for the first round bought us a press for a house warming gift for "the next time", so that was a big improvement.  We just added a little less than a cup of water to a cup of masa harina or nixtamalized corn flour and 1/8 tsp of baking soda.  I suppose that the baking powder is there to lighten the dough with CO2 produced through an acid-base reaction, but what's the acid?  I've seen many other recipes that do not call for a leavening agent and your thoughts on this issue are welcome.

Jim and Peta

Here's a picture of the nixtamalization and masa production process, 'cause food science is cool.